The present invention relates to suspension systems, and more particularly to a gas spring suspension system that includes a floating piston to maximize the travel of the suspension system.
Bicycles include suspension systems to cushion the rider from irregularities in the terrain. Bicycle suspension systems are typically located at the front fork, seat tube or at other bicycle frame locations. A typical front suspension fork includes two legs, each leg having upper and lower telescoping tubes. At least one leg includes a resilient member for biasing the upper and lower tubes apart from each other and for absorbing compressive forces applied to the fork. The resilient member may be a coil spring, an elastomer spring, a gas spring or the like.
The maximum amount the upper and lower tubes may compress relative to each other is commonly referred to as the travel of the fork. Early suspension forks were capable of about 50 mm of travel. However, as riders began to traverse rougher terrain at higher speeds, a greater amount of travel was needed to absorb the higher riding forces. Thus, later suspension forks were designed with travel settings of 140 mm or more.
Another concern of bicyclists is the overall weight of the bicycle. Typically, a coil spring or an elastomeric suspension fork adds unnecessary weight to the bicycle. To reduce the weight of the fork, a gas spring may be used. The gas spring may include a positive gas chamber to bias the upper and lower tubes apart from each other and a negative gas chamber to bias the upper and lower tubes toward each other. However, a disadvantage of such a gas spring is that during compression the entire length of the upper tube is not used. Accordingly, there is a need to provide a gas spring that uses the entire length of the upper tube.